Automatic mail sorting apparatus has become quite specialized and sophisticated over recent years with much development attention being given to the processing of letter-sized mailpieces, including mailpieces with printed address information and/or codes positioned in prescribed locations on the mailpiece face. Larger mailpieces such as mail flats typically have their address information provided on the mailpiece face but not in a particular location or code form. Sometimes the address information is printed on labels affixed to the mailpiece; other times the address information is printed directly on the mailpiece face. Such address information is generally in a block form comprised of individual characters spaced in a line and character lines spaced in an array (or block), is typically oriented parallel or perpendicular to a mailpiece principal edge, and frequently is situated in a cluttered environment or background of other printed information. In the development of automatic mail sorting apparatus for mail flats, considerable attention must therefore be given to both the problem of identifying and locating address information as well as the problem of separating the address information from any background clutter.
Numerous prior art patents describe various correlation techniques, some directed to mail-sorting applications. None, as in the case of applicant's claimed invention, satisfactorily resolve the problem of efficiently locating address information positioned on the face of a mailpiece, particularly in a cluttered background. Such prior art patents include the following summarized examples.
U.S. Pat. No. 4,333,006 Gorin et al. discloses a multifocal holographic scanning system for reading bar codes. Each scanning beam is in overlapping relationship. U.S. Pat. No. 4,034,341 Isono et al. reveals an automatic postal-code number reading system including means to detect the position of the address and mail code.
U.S. Pat. No. 3,873,181 Chivian et al. relates to infrared correlation method using thermochromics having a hysteresis property. U.S. Pat. No. 3,818,191 Feenema et al. shows automatic non-contact recognition of coded insignia using fluorescent ink in a package sorting apparatus.
U.S. Pat. No. 3,684,867 Acker discloses a device and apparatus for machine reading of information having random position and/or random orientation when passing through or placed within a particular area. A video scanner detects differences in reflected light and orientation. U.S. Pat. No. 3,801,775 Acker reveals a method and apparatus for identifying objects. Fluorescent labels are read for orientation in perpendicular directories.
U.S. Pat. No. 3,566,137 Lemmond relates to a holographic character reader using a liquid photoconductor for recording input images radiated from the surface of an object characters. U.S. Pat. No. 3,432,032 Curphey et al. shows a presorting method and apparatus.